GENEVA — It helps solve one of the most fundamental riddles of the universe: how the Big Bang created something out of nothing 13.7 billion years ago.

In what could go down as one of the great Eureka moments in physics — and win someone the Nobel Prize — scientists said Thursday that after a half-century quest, they are confident they have found a Higgs boson, the elusive subatomic speck sometimes called the ‘‘God particle.’’

The existence of the particle was theorized in 1964 by the British physicist Peter Higgs to explain why matter has mass. Scientists believe the particle acts like molasses or snow: When other tiny basic building blocks pass through it, they stick together, slow down, and form atoms.

Advertisement

Scientists at CERN, the Geneva-based European Organization for Nuclear Research, announced in July that they had found something that looked like the Higgs boson, but they were not certain, and they needed to go through the data and rule out the possibility it was not something else.

‘‘To me it is clear that we are dealing with a Higgs boson, though we still have a long way to go to know what kind of Higgs boson it is,’’ said Joe Incandela, a physicist who heads one of the two main teams at CERN, each involving about 3,000 scientists.

Whether or not it was a Higgs boson had to be demonstrated by how it interacts with other particles and its quantum properties, CERN said. The data ‘‘strongly indicates that it is a Higgs boson,’’ it said.

The discovery explains what once seemed unexplainable and still is a bit hard for the average person to comprehend. But it means the key theory that scientists use to explain everything works — for now, at least.

Advertisement

Its discovery could be a strong contender for the Nobel, though it is uncertain whether the prize would go to the 83-year-old Peter Higgs and the others who first proposed the theory, or to the thousands of scientists who found it, or to all of them.